1. Field of the Invention
The present invention relates to an IEEE 1394 network, and more particularly, to a method of generating an IEEE 1394 virtual network in which a virtual network is constructed on the IEEE 1394 network and the respective nodes sense the virtual network, and a controller for generating the virtual network.
2. Description of the Related Art
In general, an IEEE 1394 network is comprised of at least two nodes in which each node has an intrinsic node identification xe2x80x9cID.xe2x80x9d Here, the IDs of the respective nodes are sequentially determined. Namely, when there are three nodes, the node IDs are determined to be 0, 1, and 2. When there are five nodes, the node IDs are determined to be 0, 1, 2, 3, and 4. Therefore, in order to let an arbitrary node ID represent a desired predetermined node, at least as many node IDs as nodes are necessary.
When different IEEE 1394 networks in which initializations are independently performed are connected to each other by a medium, the respective nodes constructing the networks sense these networks as those having different bus IDs. Namely, it is not currently possible to let the nodes sense the different IEEE 1394 networks as those having the same bus IDs.
To solve the above problem, it is an object of the present invention to provide a method of generating an IEEE 1394 virtual network in which it is possible to install an arbitrary node ID on a network and the respective nodes sense different IEEE 1394 networks connected by a predetermined medium as the same network.
It is another object of the present invention to provide a virtual network controller for controlling the generation of the IEEE 1394 virtual network.
Accordingly, to achieve the first object, there is provided a method for generating an IEEE 1394 virtual network. This method comprises the steps of: connecting a virtual network controller for generating a virtual self ID packet including virtual node ID information required for constructing a virtual network to a predetermined IEEE 1394 network; the respective nodes and the virtual network controller constructing the IEEE 1394 network; and for determining whether the respective nodes are branches or leaves (in this network) by performing virtual bus initialization; determining parent ports and child ports with respect to ports of the respective nodes and a root node by performing a virtual tree identification; and determining physical node IDs of the respective nodes by sending the prepared virtual self ID packet.
The virtual tree identification step comprises the steps of: setting the port of a leaf node as a parent node by the virtual network controller and the leaf node sending a parent_notify signal to a branch node; and the branch node transferring a child_notify signal to the virtual network controller and the leaf node; then setting itself as a child port and becoming a root node when the branch node receives the parent_notify signal.
The step of determining the physical node ID comprises the steps of: repeating and transferring as many self ID packets as virtual node IDs through at least one virtual network controller (VNC) connected to at least one port of a root node; and the root node transferring its own self ID packet and retaining a node ID.
To achieve the second object, there is provided a virtual network controller for generating a virtual network which can be sensed by the respective nodes in the IEEE 1394 network including the root node, comprising: a storing portion, for storing as many self ID packets as virtual node IDs included in the virtual network; a main controller, for controlling the point in time at which a bus cycle generated during performing a bus initialization, a tree identification; and a self identification starts and ends; and for reading as many self ID packets as the virtual nodes stored in the storing portion during the self identification, and transferring the self ID packets to the respective nodes of the IEEE 1394 network; a digital portion, for generating a parent_notify signal required for a bus cycle of the IEEE 1394 network, including the root node and a state signal required for transferring the self ID packet, at the point in time at which the bus cycle of the main controller starts and ends during the bus initialization, the tree identification, and the self identification and for encoding the self ID packet data transferred from the main controller; and an analog portion for converting the transfer signal of the digital portion into an analog signal, converting the analog signals received from the respective nodes of the IEEE 1394 network into digital signals, and transmitting the converted signals to the digital portion.